GtkFontButton: Limit the decimals shown for size
GtkFontButton: Limit the decimals shown for size

It doesn't make sense to show a font size with 6 digits. Use
the same formatting we use in the font chooser widget now.

https://bugzilla.gnome.org/show_bug.cgi?id=724996

ahodesuka/gtk,Adamovskiy/gtk,davidgumberg/gtk,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,Lyude/gtk-,jigpu/gtk,davidgumberg/gtk,davidgumberg/gtk,ahodesuka/gtk,alexlarsson/gtk,jadahl/gtk,jigpu/gtk,jadahl/gtk,jigpu/gtk,davidgumberg/gtk,davidgumberg/gtk,davidgumberg/gtk,Adamovskiy/gtk,alexlarsson/gtk,Lyude/gtk-,ahodesuka/gtk,chergert/gtk,jessevdk/gtk,Lyude/gtk-,chergert/gtk,ahodesuka/gtk,jessevdk/gtk,chergert/gtk,alexlarsson/gtk,jadahl/gtk,jessevdk/gtk,alexlarsson/gtk,chergert/gtk,Lyude/gtk-,jessevdk/gtk,ahodesuka/gtk,Lyude/gtk-,Adamovskiy/gtk,jigpu/gtk,ahodesuka/gtk,jigpu/gtk,chergert/gtk,jigpu/gtk,jadahl/gtk,jadahl/gtk,ahodesuka/gtk,chergert/gtk,jessevdk/gtk,Adamovskiy/gtk,alexlarsson/gtk,grubersjoe/adwaita,Lyude/gtk-,davidgumberg/gtk,jessevdk/gtk,grubersjoe/adwaita,davidgumberg/gtk,Adamovskiy/gtk,chergert/gtk,Adamovskiy/gtk,grubersjoe/adwaita,grubersjoe/adwaita,chergert/gtk,alexlarsson/gtk,Lyude/gtk-,jadahl/gtk,jadahl/gtk,jigpu/gtk,ahodesuka/gtk,Adamovskiy/gtk,grubersjoe/adwaita,Lyude/gtk-,alexlarsson/gtk,Adamovskiy/gtk,jessevdk/gtk,jigpu/gtk,alexlarsson/gtk,jadahl/gtk